Stalled efforts toward comprehensive immigration reform are about more than providing a clear path to citizenship for illegal border crossers, the chief of U.S. domestic security said Monday.

Homeland Security Sec. Janet Napolitano said an overhaul of immigration laws would be a chance to strengthen enforcement tools, such as toughening penalties against employers who knowingly hire illegal workers to save money.

During a wide-ranging, 45-minute interview with the editorial board of The San Diego Union Tribune, the former Arizona governor and state attorney general said strengthening immigration rules also could lead to more high-tech resources that authorities would use to make sure visitors to the United States don't overstay their visas.

“There are areas in terms of visas and visa overstays, again, that should be addressed legally through an immigration reform bill,” Napolitano said. “We need a new legislative framework from which to act. It’s the 21st century. We need a bill that builds for that.”

She did not provide specific details on how an immigration bill would address visas overstays and other enforcement challenges.

Much of the public conversation about immigration reform has focused on clarifying regulations for people who aspire to become legal residents or citizens, and whether an amnesty program would undermine enforcement efforts against more illegal immigrants.

Napolitano tried to show Monday that immigration is also about homeland security, touching on a crucial security issue related to the 9/11 attacks and the perpetrators whose visas had expired.

She said the U.S. is doing much more than before to check the background of visa applicants before they enter the country, but that “we don’t have the capacity yet to monitor every visa overstaying and find them.”

Napolitano also portrayed immigration reform, which has been postponed at least until after the November elections, as an opportunity to go after businesses that deliberately hire employees without the proper documents.

“One of the parts that doesn’t get mentioned enough is we need more enforcement tools than current law provides,” Napolitano said. “And one of the areas where we need a better deterrent in is the whole employer side .... To prove an employer case is very difficult under the way the current law is written, and secondly, the penalty is not that great.”

Under Napolitano, Immigration and Customs Enforcement has increased the number of I-9 audits, in which agents review whether employers are properly verifying the legal status of employees.